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Rework pbuf_add_header_impl to only modify the pbuf after all checks passed

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This commit is contained in:
goldsimon 2017-08-08 12:19:06 +02:00
parent 6209c8d347
commit ae7c76c773
1 changed files with 9 additions and 11 deletions
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20
src/core/pbuf.c
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@ -487,20 +487,16 @@ pbuf_add_header_impl(struct pbuf *p, size_t header_size_increment, u8_t force)
} }
type_internal = p->type_internal; type_internal = p->type_internal;
/* remember current payload pointer */
payload = p->payload;
/* pbuf types containing payloads? */ /* pbuf types containing payloads? */
if (type_internal & PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS) { if (type_internal & PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS) {
/* set new payload pointer */ /* set new payload pointer */
p->payload = (u8_t *)p->payload - header_size_increment; payload = (u8_t *)p->payload - header_size_increment;
/* boundary check fails? */ /* boundary check fails? */
if ((u8_t *)p->payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) { if ((u8_t *)payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) {
LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE, LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE,
("pbuf_header: failed as %p < %p (not enough space for new header size)\n", ("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
(void *)p->payload, (void *)((u8_t *)p + SIZEOF_STRUCT_PBUF))); (void *)payload, (void *)((u8_t *)p + SIZEOF_STRUCT_PBUF)));
/* restore old payload pointer */
p->payload = payload;
/* bail out unsuccessfully */ /* bail out unsuccessfully */
return 1; return 1;
} }
@ -508,19 +504,21 @@ pbuf_add_header_impl(struct pbuf *p, size_t header_size_increment, u8_t force)
} else { } else {
/* hide a header in the payload? */ /* hide a header in the payload? */
if (force) { if (force) {
p->payload = (u8_t *)p->payload - header_size_increment; payload = (u8_t *)p->payload - header_size_increment;
} else { } else {
/* cannot expand payload to front (yet!) /* cannot expand payload to front (yet!)
* bail out unsuccessfully */ * bail out unsuccessfully */
return 1; return 1;
} }
} }
/* modify pbuf length fields */ LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_header: old %p new %p (%"U16_F")\n",
(void *)p->payload, (void *)payload, increment_magnitude));
/* modify pbuf fields */
p->payload = payload;
p->len = (u16_t)(p->len + increment_magnitude); p->len = (u16_t)(p->len + increment_magnitude);
p->tot_len = (u16_t)(p->tot_len + increment_magnitude); p->tot_len = (u16_t)(p->tot_len + increment_magnitude);
LWIP_DEBUGF(PBUF_DEBUG | LWIP_DBG_TRACE, ("pbuf_header: old %p new %p (%"U16_F")\n",
(void *)payload, (void *)p->payload, increment_magnitude));
return 0; return 0;
} }